The present invention relates in general to the field of (bio)chemical sensors and more specifically to a miniaturized integrated sensor platform suitable for use as an optic-based sensoring device.
Without limiting the scope of the invention, its background is described in connection with a (bio)chemical sensor wherein a thin film, fiber or other article is chemically treated with a substance known to interact in the presence of a second substance so as to produce a reaction which can be detected and quantified by analytical methods.
(Bio)chemical sensor systems have been developed and used in the fields of chemical, biochemical, biological or biomedical analysis, process control, pollution detection and control and other areas. A typical application involves the chemical coating of a thin film, cable or other article followed by excitation and measurement in the presence of the particular sample of interest. Recent advances in miniaturized sensor technology have resulted in three popular configurations: fluorescence-based, surface plasmon resonance, and light transmission sensors.
A known prior art sensor system is the fluorescence-based fiber optic oxygen cable sensor which uses a single high brightness Light Emitting Diode (LED)to produce an excitation signal that catalyzes the emission properties of the fluorescence coating material. The excitation signal is first guided through a filter and then through the cable, which is coated, unclad, and mounted in a gas flow cell. Light escaping the cell excites the coated dye on the cable which, in turn, emits a certain intensity of light related to the concentration of the oxygen sample. The emitted light is then directed through a second filter and to a light detector via a collecting lens. The output of the detector is amplified and read out on an instrument.
Another known prior art sensor system uses a multi-pin hermetically sealed package that encloses all of the light filtering, light guiding and light detection components within. The package can be inserted into a socket or slot of a computer or other system processor creating an interface between the sensor and the processor via the pins. Due to the number of pins, however, replacing, removing or inserting the chip may be difficult or require special tools.
Prior art sensor systems have limited use in most practical field applications. The signal generator, LED, lens, filter, detector, amplifier and other components are bulky, require significant amounts of work space and cannot be easily transported to the sample site. The costs of manufacturing and maintaining such systems are high prohibiting high volume manufacturing.
Moreover, prior art sensors are not designed for low cost disposable applications wherein the sensor can be disposed after serving its useful life. A cost effective sensor having an onboard power cell has not been contemplated and, as such, prior art sensor packages require an interface to an external power supply or other source of operating power.
Another limitation of the prior art sensors the number and types of components used which in many instances are custom made based on the particular application. System maintenance is high and requires specialized knowledge.
Yet another limitation of the prior art sensors is system integration with equipment such as a personal computers, hand held instruments or other signal processors used to measure and quantify sample data. A dedicated bus or interface between the sensor and the processor is required increasing the number of signal paths between the sensors detector and the processor.
Prior art sensors can not be used in most disposable and field use applications. The recent availability of low cost high intensity light sources and miniaturized detector components, however, permits the design of a more compact and miniaturized sensor platform. A miniaturized sensor would provide many advantages over the bulkier prior art sensor systems which are better suited for laboratory and research applications.
As such, it is a primary object of the present invention to provide a miniaturized integrated sensor capable of use in optically guided sensing applications. The sensor package of the present invention integrates a light source, detector means, light guide optics and a simplified system interface into a compact miniaturized package. In one embodiment, the package incorporates an onboard power source, such as a lithium cell battery of the type readily available in industry, giving the sensor a useful lifetime equal to that of the power source. Thus, a fully operable sensor is disclosed that can be easily replaced and discarded after use.
Another object of the present invention is to provide a miniaturized sensor with a simplified interface to external systems such as computers, signal processors, and other similar processors which perform analytical processing of the output from the sensor""s light detector. In one embodiment, the sensor package has a three-pin lead frame extending from the platform with signal conduits to power, ground and the detector output. In a second embodiment, a two-pin version is provided wherein the onboard power source eliminates the need for a third signal interface.
Yet another object of the present invention is to provide a sensor with a uniquely shaped package which fits securely into an opening or mounting harness in a hand held instrument, computer or other similar fixture. In one embodiment, the sensor housing is shaped and sized to fit a fixture in a hand held application specific instrument which uses the sample data from the sensor to perform further signal processing and analytical functions. Surface contacts on the sensor walls provide the interface with the instrument. Since the device is uniquely shaped it fits into the mounting harness about a predetermined position allowing simple insertion and removal.
Disclosed in one embodiment of the invention, is an integrated sensor for detecting the presence of one or more specific material samples of interest having a platform to which a light source, detector, waveguide and reflective pyramidal structures are affixed to form a miniaturized fully integrated sensor package. A three-pin lead frame extends from the sensor package providing the interface between the sensor and an external processor. In another embodiment, surface contacts provide the same function. Power can be external or provided internally by a self contained battery cell which is coupled to the platform and the various active components of the sensor. In yet another embodiment, the package is uniquely shaped and sized requiring a unique placement within a mounting harness in a computer, hand held instrument, wall mount harness or other similar fixture.
For a more complete understanding of the present invention, including its features and advantages, reference is now made to the following detailed description, taken in conjunction with the accompanying drawings.